docs: def Lombardi_Pedrocchi(m, x, rhol, rhog, sigma, D, L=1):
      r'''Calculates two-phase pressure drop with the Lombardi-Pedrocchi (1972)
      correlation from [1]_ as shown in [2]_ and [3]_.
  
      .. math::
          \Delta P_{tp} = \frac{0.83 G_{tp}^{1.4} \sigma^{0.4} L}{D^{1.2}
          \rho_{h}^{0.866}}
  
      Parameters
      ----------
      m : float
          Mass flow rate of fluid, [kg/s]
      x : float
          Quality of fluid, [-]
      rhol : float
          Liquid density, [kg/m^3]
      rhog : float
          Gas density, [kg/m^3]
      sigma : float
          Surface tension, [N/m]
      D : float
          Diameter of pipe, [m]
      L : float, optional
          Length of pipe, [m]
  
      Returns
      -------
      dP : float
          Pressure drop of the two-phase flow, [Pa]
  
      Notes
      -----
      This is a purely empirical method. [3]_ presents a review of this and other
      correlations. It did not perform best, but there were also correlations
      worse than it.
  
      Examples
      --------
      >>> Lombardi_Pedrocchi(m=0.6, x=0.1, rhol=915., rhog=2.67, sigma=0.045,
      ... D=0.05, L=1)
      1567.328374498781
  
      References
      ----------
      .. [1] Lombardi, C., and E. Pedrocchi. "Pressure Drop Correlation in Two-
         Phase Flow." Energ. Nucl. (Milan) 19: No. 2, 91-99, January 1, 1972.
      .. [2] Mekisso, Henock Mateos. "Comparison of Frictional Pressure Drop
         Correlations for Isothermal Two-Phase Horizontal Flow." Thesis, Oklahoma
         State University, 2013. https://shareok.org/handle/11244/11109.
      .. [3] Turgut, Oğuz Emrah, Mustafa Turhan Çoban, and Mustafa Asker.
         "Comparison of Flow Boiling Pressure Drop Correlations for Smooth
         Macrotubes." Heat Transfer Engineering 37, no. 6 (April 12, 2016):
         487-506. doi:10.1080/01457632.2015.1060733.
      '''
      voidage_h = homogeneous(x, rhol, rhog)
      rho_h = rhol*(1-voidage_h) + rhog*voidage_h
      G_tp = m/(pi/4*D**2)
      return 0.83*G_tp**1.4*sigma**0.4*L/(D**1.2*rho_h**0.866)